So, this is an out there question. If I were to change to intake, carb, and put electronic ignition on an OBD2 magnum, would the transmission shift shift manually through 1,2,3? This is a SHTF scenario I have wondered about.

RE will launch in 3rd with electronics dead since in default the governor solenoid is not being modulated ( so you develop full governor pressure ) so if you pull it in manual low it should launch in 1st then you can upshift manually.

GV makes a version for the PG (now) that splits gears, making the 2-speed a 3-speed with the overdrive, but also creating an intermediate gear between 1st and 2nd.This can be done manually with a 727 conversion + GV, not sure if it's possible to do electronically (rather than try to juggle both controls).The results for a 727:1st 2.45:11st + GV 1.91:12nd 1.45:12nd + GV 1.13:13rd 1.00:13rd + GV .78:1

To the same level that a properly built 727 will- provided you don't hot rod it with OD engaged. Transmissions are really rated on torque output not horsepower anyways.

Correct me if I'm wrong here, but don't the first 3 gears go through an additional clutch pack in the 518s? A clutch pack that must release for OD. Without proper attention, that could be a point of concern that 727s don't have.

The power from the trans goes through the over running clutch (ORC) and direct clutch in the overdrive unit. I have never seen a failed ORC and direct clutch in the over drive as long as the trans was assembled correctly. The same direct clutch and ORC is use daily in the diesel units as the gas units.

The direct clutch is also used in reverse and is used to slow the vehicle down on coast in forward gears.

The clutch that needs proper attention is the overdrive clutch because the correct shim must be used on the OD piston to time the release of the direct with the application of the OD.

Are there any trans tunnel mods needed in a B-body for the 518 trans?I know it's a pretty large amount of work in an A-body.

Even though the Gearvendors is only a .78 overdrive I think it would be good enough for me and an easier install. And I like how it will handle full power for an occasional highway brawl.

That's kind of what I was thinking. I have 3.73's with a CRT 727 and I'm turning around 3000 RPM's at 55-60. I know GV is only .78 vs. .69 but if I can keep it around 24-2500 at 70mph I'm good.

I'm a fan of the 518. I have one behind a 512 stroker mated with an Ultra Bell. Between the bell, converter and transmission I've got about $1800 into it. OD shifts are controlled with a pressure switch and a vacuum switch. If you've already got a trans built by CRT though I'd be inclined to go with the GV too.

Darren at ProTrans built my buddies A518 for his '66 Coronet, needed quite a bit of work to the tunnel and floor to get it in. He has a 470" motor, bottom 11's on motor, low 10s on juice, his has a lockup convertor.I have a GV in my '70 Cuda, only had to trim the trans crossmember some and put a few dents in the floorboard to get it in.

Registered: 12/18/09
Posts: 9820
Loc: in a cattle trailer down by th...

Originally Posted By WO23Coronet

Can they be built to tow in OD and live? Say a 5500lb truck towing a 8-9K loaded car hauler?

I've towed my 30' enclosed at around 12K lbs. with a 47RH and a 48RE with never a problem. Never turned the O/D off. I used to tow about 5K lbs around with my 5.2 Dakota and a 518 (46RH) and had no problems with that either.